Management of Carpobrotus edulis
Carpobrotus edulis (Aizoaceae: EPPO List of Invasive Alien Plants) is native to South Africa and is a succulent species which invades temperate coastal areas around the world. The species has been shown to modify the environment where it invades, and it affects the composition, diversity and dynamics of native plant communities due to its mat forming habit. Within the EPPO region, C. edulis can grow in a variety of habitats including coastal dune systems, rock ledges, and cliffs. Invasion in such habitats, particularly the latter, can have implications for successful management as some of the areas where plants may persist are difficult to access. Managing the species can include a number of methods such as hand removal, herbicides and mulching, though these are labour intensive and plant material should be removed and disposed of, as fragments of C. edulis can re-root following hand removal. The present study evaluated the regeneration capacity of plant fragments placed on different substrates (sand and stones) and assessed if herbivory, by the specialist South African scale insect Pulvinariella mesembryanthemi (introduced accidentally probably with its host plants into the EPPO region) reduces the regeneration capacity. Plant material and the natural enemy were collected from sites near Baiona, Spain. Fragments of C. edulis were placed on stone, sand on bare ground (the control), with and without P. mesembryanthemi. The results showed that regardless of the substrate, the specialist herbivore greatly reduced C. edulis regeneration, and biomass. The decomposition of C. edulis was accelerated by combining biological control with preventing re-rooting by avoiding connection to the soil.
Sources
Nǔňá N, Rodríguez J, González L (2021) Managing the invasive plant Carpobrotus edulis: is mechanical control or specialized natural enemy more effective? Journal of Environmental Management. https://doi.org/10.1016/j.jenvman.2021.113554